Tests: Remove use of assertArraySubset() in `Test_WP_Widget_Media::…

…test_constructor()`.

The `assertArraySubset()` method has been deprecated in PHPUnit 8 and removed in PHPUnit 9.

This replaces the assertions with looping through the array and testing both the key and the value individually.

References:
* https://github.com/sebastianbergmann/phpunit/blob/8.0.6/ChangeLog-8.0.md#800---2019-02-01
* sebastianbergmann/phpunit#3494

Note: There is a polyfill package available for the removed assertion: `dms/phpunit-arraysubset-asserts`, but as the assertion was only used in this one test method, adding this seems redundant.

Follow-up to [51559-51568].

Props jrf.
See #46149.
Built from https://develop.svn.wordpress.org/trunk@51569


git-svn-id: http://core.svn.wordpress.org/trunk@51180 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.9-alpha-51568';
+$wp_version = '5.9-alpha-51569';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.